Functionalization of two-dimensional 1T'-ReS with surface ligands for use as a photocatalyst in the hydrogen evolution reaction: a first-principles calculation study.

Density functional theory calculations were performed to tune the band edge positions of two-dimensional 1T'-ReS2 by functionalization with surface ligands. A shift in the band edge was caused by the intrinsic dipole of the ligand and the induced dipole at the ligand/ReS2 interface. The upward shift in the band edge was tuned over a large range by choosing suitable polar ligands, controlling the surface coverage by the ligand, functionalizing the ligand and building heterostructures. The C6H5CN/ReS2/MoS2 and C6H5CH2CN/ReS2/MoS2 van der Waals heterostructures are ideal candidates for use as photocatalysts in the splitting of water as a result of their strong absorption in the visible region, suitable band edge positions, reduced electron-hole recombination and good stability. Our findings show the potential for creating novel photocatalysts based on van der Waals heterostructures of ReS2.